U.S. patent number 4,547,567 [Application Number 06/631,999] was granted by the patent office on 1985-10-15 for derivatives of 4'-demethyl-4-epipodophyllotoxin.
This patent grant is currently assigned to Zaidan Hojin Biseibutsu Kagaku Kenkyu Kai. Invention is credited to Shinichi Kondo, Yoshio Nishimura, Tomio Takeuchi, Tomohisa Takita, Wataru Tanaka, Hamao Umezawa, Hiroshi Yoshikawa.
United States Patent |
4,547,567 |
Umezawa , et al. |
October 15, 1985 |
Derivatives of 4'-demethyl-4-epipodophyllotoxin
Abstract
This invention relates to novel 4'-demethyl-4-epipodophyllotoxin
derivatives represented by the general formula (I), and salts
thereof: ##STR1## wherein R is a lower alkyl group, and X.sub.1 and
X.sub.2 are independently a hydroxyl group or an amino group, the
one being an amino group and the other being a hydroxyl group.
These novel derivatives have a high carcinostatic activity and a
relatively high water solubility and hence are expected to be
useful as carcinostatics.
Inventors: |
Umezawa; Hamao (Tokyo,
JP), Takeuchi; Tomio (Tokyo, JP), Kondo;
Shinichi (Yokohama, JP), Tanaka; Wataru (Houya,
JP), Takita; Tomohisa (Asaka, JP),
Nishimura; Yoshio (Yokohama, JP), Yoshikawa;
Hiroshi (Fujioka, JP) |
Assignee: |
Zaidan Hojin Biseibutsu Kagaku
Kenkyu Kai (Tokyo, JP)
|
Family
ID: |
15204455 |
Appl.
No.: |
06/631,999 |
Filed: |
July 18, 1984 |
Foreign Application Priority Data
|
|
|
|
|
Jul 29, 1983 [JP] |
|
|
58-137687 |
|
Current U.S.
Class: |
536/17.2;
536/18.1 |
Current CPC
Class: |
C07H
17/04 (20130101); A61P 35/00 (20180101); Y02P
20/55 (20151101) |
Current International
Class: |
C07H
17/04 (20060101); C07H 17/00 (20060101); C07H
015/24 () |
Field of
Search: |
;536/17.2,18.1 |
References Cited
[Referenced By]
U.S. Patent Documents
|
|
|
3060169 |
October 1962 |
Stoll et al. |
3408441 |
October 1968 |
von Wartburg et al. |
3524844 |
August 1970 |
Keller-Juslem et al. |
|
Primary Examiner: Brown; Johnnie R.
Attorney, Agent or Firm: Banner, Birch, McKie &
Beckett
Claims
What is claimed is:
1. A novel 4'-demethyl-4-epipodophyllotoxin derivative represented
by the formula, or a salt thereof: ##STR9## wherein R is a lower
alkyl group, and X.sub.1 and X.sub.2 are independently a hydroxyl
group or an amino group, when one is an amino group the other is a
hydroxyl group.
2. A 4'-demethyl-4-epipodophyllotoxin derivative or a salt thereof
according to claim 1, wherein R is a methyl group, an ethyl group
or a propyl group.
3. 4-O-(2-amin
o-2-deoxy-4,6-O-ethylidene-.beta.-D-glucopyranosyl)-4'-demethyl-4-epipodoph
yllotoxin and salts thereof.
4. 4-O-(3-amino-3-deoxy-4,6-
O-ethylidene-.beta.-D-glucopyranosyl)-4'-demethyl-4-epipodophylotoxin
and salts thereof.
Description
BACKGROUND OF THE INVENTION
4'-Demethyl-epipodophyllotoxin-alkylidene-.beta.-D-glucoside
(hereinafter referred to as "etoposide") has heretofore been well
known as a compound having an antitumor effect by U.S. Pat. No.
3,524,844 and the like.
In order to develop a more excellent antitumor agent, the present
inventors have made an extensive study and have consequently found
that a compound of the general formula (I) has an excellent
antitumor activity and has a very high water solubility as compared
with etoposide, whereby this invention has been accomplished.
SUMMARY OF THE INVENTION
An object of this invention is to provide novel
4'-demethyl-4-epipodophyllotoxin derivatives having an excellent
antitumor activity and a high water solubility, salts thereof and a
process for producing them.
Other objects and advantages of this invention will be made
apparent by the following descriptions.
DETAILED DESCRIPTION OF THE INVENTION
This invention relates to novel 4'-demethyl-4-epipodophyllotoxin
derivatives represented by the general formula (I), and salts
thereof: ##STR2## wherein R is a lower alkyl group, and X.sub.1 and
X.sub.2 are independently a hydroxyl group or an amino group, the
one being an amino group and the other being a hydroxyl group.
The compound of the above general formula (I) of this invention can
be obtained by reacting a compound represented by the general
formula (V): ##STR3## wherein one of X.sub.1 " and X.sub.2 " is a
hydroxyl group or a protected hydroxyl group and the other is an
amino group or a protected amino group, and Y.sub.1 is hydrogen or
a protecting group, with an aldehyde represented by the general
formula (VI), or an acetal compound thereof:
wherein R is a lower alkyl group, to obtain a compound represented
by the general formula (VII): ##STR4## wherein X.sub.1 ", X.sub.2 "
and Y.sub.1 are as defined above, and then removing protecting
groups by a conventional method to obtain the general formula (I)
when the general formula (VII) contains the protecting group, but
when X.sub.1 ", X.sub.2 " and Y.sub.1 in the general formula (VII)
do not contain the protecting group, the general formula (VII)
becomes the same as the general formula (I).
The reaction of a compound of the general formula (V) with an
aldehyde of the general formula (VI) or an acetal compound thereof
is usually effected in a solvent in the presence of an acid
catalyst, preferably, a sulfonic acid, cation-exchange resin and
Lewis acid. The molar ratio of (VI) to (V) is usually 0.5 to 100,
preferably 1 to 10. As the sulfonic acid, arylsulfonic acids such
as p-toluenesulfonic acid and the like are preferred, and the used
amount thereof is usually 0.01 to 10% by weight preferably 0.1 to
5% by weight based on the sum of the compounds of (V) and (VI).
The solvent is not limited so long as it is inert, and there may
usually be used, for example, polar organic solvents such as
acetonitrile, nitromethane, dioxane and the like.
The reaction temperature is usually at -10.degree. C. to
100.degree. C., preferably -5.degree. C. to 50.degree. C., more
preferably 0.degree. C. to 30.degree. C. The reaction time is 5
minutes to 10 hours, preferably 10 minutes to 3 hour.
For the removal of the protecting groups from the compound of the
general formula (VII), there may be employed any of the well-known
methods and the methods include reduction (e.g., catalytic
reduction using a Pd catalyst or a Pt catalyst), acid decomposition
(e.g., acid decomposition using hydrogen halogenide such as HCl and
HBr, acetic acid, trifluoroacetic acid, trifluoromethanesulfonic
acid or the like), a method of removing the protecting groups by
reacting an amine with said compound, a method of removing the
protecting groups by reacting an alcohol (a lower alcohol such as
methanol, ethanol or the like) with said compound in the presence
of a catalyst (e.g., zinc powder, lead powder or a metal salt of an
organic acid such as zinc acetate or the like), etc.
The lower alkyl group for R in the general formula (VI) includes,
for example, a methyl group, an ethyl group, a propyl group, etc.,
and a methyl group is particularly preferred.
The aldehyde of the general formula (VI) or the acetal thereof
include, for example, acetaldehyde, propionaldehyde, and
acetaldehyde diloweralkylacetal such as acetaldehyde
dimethylacetal, acetaldehyde diethylacetal and acetaldehyde
dipropylacetal.
The kinds of protecting group for the amino group and the
protecting group for the hydroxyl group in the general formula (V)
or (VII) are not critical.
For example, the protecting group for the amino group includes
lower alkoxycarbonyl groups such as butoxycarbonyl group,
benzyloxycarbonyl group and substituted benzyloxycarbonyl groups
having on the phenyl group one or more substituents (for example,
lower alkyl groups, lower alkoxy groups, halogen atoms such as Cl
or Br, or the like), a benzyl group, halogen-substituted lower acyl
groups (e.g., a trifluoroacetyl group, a monochloroacetyl group,
etc.), and the like.
The protecting group for the hydroxyl group includes lower acyl
groups such as an acetyl group, halogen-substitued acetyl groups
and the like, a pyranyl group, the aryl-substituted
lower-alkoxycarbonyl groups exemplified above as the aforesaid
protecting group for the amino group, etc.
The compound of the general formula (V) is produced in the
following process.
4'-O-protected-4'-demethyl-4-epipodophyllotoxin represented by the
general formula (II): ##STR5## wherein Y.sub.1 is as defined above,
is reacted with a compound represented by the general formula
(III): ##STR6## wherein Y.sub.2 and Y.sub.3 are independently a
protecting group, one of X.sub.1 ' and X.sub.2 ' is a protected
amino group and the other is a protected hydroxyl group, in an
inert solvent in the presence of a catalyst for condensation, for
example, boron trifluoride-diethyl ether or the like to obtain a
compound represented by the general formula (IV): ##STR7## wherein
Y.sub.1, Y.sub.2, Y.sub.3, X.sub.1 ' and X.sub.2 ' are as defined
above. Subsequently, the protecting groups for Y.sub.2 and Y.sub.3
are removed. At the time of removing the protecting groups for
Y.sub.2 and Y.sub.3, the protecting group for the hydroxyl group in
X.sub.1 ' or X.sub.2 ' and Y.sub.1 may be removed, and if
necessary, the remaining protecting group or groups in X.sub.1 '
and/or X.sub.2 ' and the protecting group for Y.sub.1 may be then
removed if Y.sub.1 is a protecting group.
Thus, the compound of the general formula (V) can be obtained.
The compound of the general formula (I) of this invention can be
converted into a salt thereof with an acid by a conventional
method, and as the salt, there may be exemplified salts with
inorganic acids or organic acids such as hydrochloric acid,
sulfuric acid, phosphoric acid, acetic acid, citric acid or the
like.
Next, typical compounds of this invention and their physical
property values are shown below.
(1)
4-O-(2-amino-2-deoxy-4,6-O-ethylidene-.beta.-D-glucopyranosyl)-4'-demethyl
-4-epipodophyllotoxin. (Compound No. 1) (hereinafter referred to as
2-amino compound)
Melting point: 201.degree.-215.degree. C.
Specific rotation: [.alpha.].sub.D.sup.21 -89.8.degree. (CH.sub.3
OH)
MS (SIMS): 588 (M+H).sup.+
NMR (Pyridine-d.sub.5): .delta.1.36 (3H, d, CH.sub.3), .delta.3.74
(6H, s, OCH.sub.3), .delta.5.05 (1H, d, H-4), .delta.5.24 (1H, d,
H-1), .delta.5.92 (2H, s, --O--CH.sub.2 --O--), .delta.6.72 (1H, s,
H-8), .delta.6.75 (2H, s, H-2', 6'), .delta.7.45 (1H, s, H-5)
IR: 1764 (C.dbd.O)cm.sup.-1
(2)
4-O-(3-amino-3-deoxy-4,6-O-ethylidene-.beta.-D-glucopyranosyl)-4'-demethyl
-4-epipodophyllotoxin. (Compound No. 2) (hereinafter referred to as
3-amino compound)
Melting point: 210.degree.-220.degree. C.
Specific rotation: [.alpha.].sub.D.sup.23 -94.7.degree.
(CHCl.sub.3)
MS (SIMS): 588 (M+H).sup.+
NMR (CDCl.sub.3): .delta.1.35 (3H, d, CH.sub.3), .delta.3.77 (6H,
s, --OCH.sub.3), .delta.4.90 (1H, d, H--4), .delta.5.97 (2H, broad
s, --O--CH.sub.2 --O--), .delta.6.27 (2H, s, H-2', 6'), .delta.6.55
(1H, s, H-8), .delta.6.85 (1H, s, H-5)
IR: 1765 (C.dbd.O)cm.sup.-1
These compounds have very potent antitumor activity.
The antitumor activity of the compound according to this invention
was investigated in the following way:
EXPERIMENTAL EXAMPLE 1
(Test of Antitumor Activity)
10.sup.5 murine leukemia L1210 cells were inoculated
intraperitoneally into mice, and a suspension of the compound of
this invention in physiological saline solution was administered
intraperitoneally once daily for 9 consecutive days, starting 24
hours after the inoculation. The animals were observed for 41 days,
and the survival rates (T/C) in these animals were calculated from
the following equation: ##EQU1##
The control group was administered physiological saline solution
only. The average survival period for the control group was 7.9 to
8.3 days.
Compound No. 1 in a dose of 100 .mu.g/mouse/day was found to give
T/C of 494 or more, and Compound No. 2 in a dose of 25
.mu.g/mouse/day, T/C of 430 or more.
EXPERIMENTAL EXAMPLE 2
(Test of Antitumor Activity)
10.sup.5 murine leukemia L1210 cells were inoculated into mice
(female CDF.sub.1, 6 weeks old), and the hydrogen chloride salt of
Compound No. 1 (2-amino compound) was administered
intraperitoneally once daily for 5 consecutive days, starting 24
hours after the inoculation. The control group was administered
physiological saline solution alone in the same manner as described
above. Whether the animals were alive or dead was observed for 60
days after the beginning of the administration and the survival
rates were calculated in the same manner as in Experimental Example
1 to find that when Compound No. 1 was administered in a dose of 10
mg/kg, the survival rates (T/C %) was 597 and the average survival
period was 43.6.+-.23.5 days. On the 60th day, mice which survived
were three of six mice per group.
As is evident from these results, the compounds of this invention
have a very excellent antitumor effect.
EXPERIMENTAL EXAMPLE 3
(Solubility test)
In a test tube was placed 11.75 mg of the hydrogen chloride salt of
Compound No. 1 (2-amino compound), and 0.5 ml of distilled water
was added. The test tube was stored at 25.degree. C. with
occasional shaking, and after 6 hr and 29 hr, sampling in an amount
of 50 .mu.l each was conducted. After each sample was filtered, 30
.mu.l of the filtrate was diluted with 4 ml of water, and then the
absorbance at 285 nm was measured.
The concentration was calculated assuming that E.sub.1 cm.sup.1%
(285 nm, H.sub.2 O)=59.6. The results are shown below.
______________________________________ OD.sub.285 Concentration
______________________________________ 6 hr 62.03 10.4 mg/ml 29 hr
64.08 10.7 mg/ml ______________________________________
Etoposide was examined for water solubility by the same test as
described above to find that its concentration was 0.1 mg/ml.
Compound No. 2 (the hydrogen chloride salt of the 3-amino compound)
was examined for water solubility in the same manner as described
above to show substantially the same water solubility as that of
Compound No. 1 (the hydrogen chloride salt of the 2-amino
compound).
The results described above indicate that the compounds of this
invention are very superior to etoposide in water solubility.
The synthesis of the compounds according to this invention will be
described in greater detail with reference to the following
Examples:
EXAMPLE 1
(1) Synthesis of
4-O-(2-benzyloxycarbonylamino-2-deoxy-.beta.-D-glucopyranosyl)-4'-benzylox
ycarbonyl-4'-demethyl-4-epipodophyllotoxin
(a) 500 mg of 4'-benzyloxycarbonyl-4'-demethyl-4-epipodophyllotoxin
and 620 mg of
3,4,6-tri-O-acetyl-2-benzyloxycarbonylamino-2-deoxy-.beta.-D-glucopyranose
were dissolved in 1 ml of dichloromethane. In the solution cooled
at -18.degree. C., 0.5 ml of BF.sub.3.Et.sub.2 O was added dropwise
over 3 minutes, and the mixture was reacted for 30 minutes, in an
atmosphere of argon. 0.5 ml of pyridine was added to terminate the
reaction, and the reaction mixture was diluted with 20 ml of
dichloromethane. The organic layer was washed twice with 10 ml of
water, dried over anhydrous Na.sub.2 SO.sub.4, and concentrated.
The concentrate was subjected to silica gel chromatography for
separation and purification. 700 mg of
4-O-(3,4,6-tri-O-acetyl-2-benzyloxycarbonylamino-2-deoxy-.beta.-D-gluropyr
anosyl)-4'-benzyloxycarbonyl-4'-demethyl-4-epipodophyllotoxin was
obtained.
Specific rotation: [.alpha.].sub.D.sup.21 -39.6.degree.
(CHCl.sub.3)
(b) 600 mg of the compound obtained in the above step and 115 mg of
zinc acetate were dissolved in 5 ml of methanol, and the solution
was boiled for 6 hours under reflux to cause the reaction. The
reaction mixture was evaporated to dryness, and 20 ml of
dichloromethane and 10 ml of water were added to the residue. The
mixture was shaken vigorously, and the organic layer was separated.
The separated layer was dried over anhydrous Na.sub.2 SO.sub.4 and
concentrated. The concentrate was subjected to silica gel
chromatography for separation and purification. 295 mg of
4-O-(2-benzyloxycarbonylamino-2-deoxy-.beta.-D-glucopyranosyl)-4'-benzylox
ycarbonyl-4'-demethyl-4-epipodophyllotoxin was obtained.
Specific rotation: [.alpha.].sub.D.sup.17 -57.2.degree.
(CHCl.sub.3)
(2-1) Synthesis of
4-O-(2-amino-2-deoxy-4,6-O-ethylidene-.beta.-D-glucopyranosyl)-4'-demethyl
-4-epipodophyllotoxin
(a) 60 mg of
4-O-(2-benzyloxycarbonylamino-2-deoxy-.beta.-D-glucopyranosyl)-4'-benzylox
ycarbonyl-4'-demethyl-4-epidodophyllotoxin in the above step was
dissolved in a solvent mixture of 1 ml of water and 2 ml of
acetone. 10 mg of palladium black was added to the solution, and
the mixture was stirred for 3 hours, with hydrogen blown
therethrough, to perform reduction. The reaction mixture was
filtered, and the filtrate was concentrated to dryness. The
concentrate was subjected to silica gel chromatography for
separation and purification. 70 mg of
4-O-(2-amino-2-deoxy-.beta.-D-glucopyranosyl)-4'-demethyl-4-epipodophyllot
oxin was obtained.
Specific rotation: [.alpha.].sub.D.sup.17 -74.7 (CH.sub.3 OH)
(b) 50 mg of the compound obtained in the above step and 0.5 ml of
acetaldehyde diethylacetal were dissolved in 2 ml of acetonitrile.
2 mg of p-toluenesulfonic acid was added to the solution, and the
mixture was stirred for 30 minutes at room temperature. Sodium
bicarbonate was added to the mixture, and the insolubles were
separated by filtration. The filter cake was washed with
dichloromethane, and the washings were combined with the filtrate,
followed by concentrating the combined liquid. The concentrate was
chromatographed on cilica gel for separation and purification. 45
mg of
4-O-(2-amino-2-deoxy-4,6-O-ethylidene-.beta.-D-glucopyranosyl)-4'-demethyl
-4-epipodophyllotoxin was obtained.
In this process, cation-exchange resin such as Amberlite.sup..RTM.
200 or Lewis acid such as ZnCl.sub.2 in place of p-toluenesulfonic
acid could be used as catalyst for condensation.
(2-2) Synthesis of
4-O-(2-amino-2-deoxy-4,6-O-ethylidene-.beta.-D-glucopyranosyl)-4'-demethyl
-4-epipodophyllotoxin
(a) 180 mg of
4-O-(2-benzyloxycarbonylamino-2-deoxy-.beta.-D-glucopyranosyl)-4'-benzylox
ycarbonyl-4'-demethyl-4-epipodophyllotoxin and 0.5 ml of
acetaldehyde diethylacetal were dissolved in 5 ml of acetonitrile.
10 mg of p-toluenesulfonic acid was added to the solution, and the
mixture was stirred for 30 minutes at room temperature. Sodium
bicarbonate was added to the mixture, and the insolubles were
separated by filtration. The filter cake was washed with
dichloromethane, and the washings were combined with the filtrate,
followed by concentrating the combined liquid. The concentrate was
chromatographed on silica gel for separation and purification. 171
mg of
4-O-(2-benzyloxycarbonylamino-2-deoxy-4,6-O-ethylidene-.beta.-D-glucopyran
osyl)-4'-benzyloxycarbonyl-4'-demethyl-4-epipodophyllotoxin was
obtained.
Specific rotation: [.alpha.].sub.D.sup.18 -54.1.degree.
(CHCl.sub.3)
In this process, acetaldehyde in place of acetaldehyde
diethylacetal was used and treated as the same way to obtain the
object compound.
(b) 171 mg of the compound obtained in the above step was dissolved
in a solvent mixture of 3 ml of ethyl acetate and 2 ml of acetone.
10 mg of palladium black was added to the solution, and the mixture
was stirred for 3 hours, with hydrogen blown therethrough, to
perform reduction. The reaction mixture was filtered, and the
filtrate was concentrated to dryness. Recrystallization from ethyl
acetate gave 73 mg of the desired
4-O-(2-amino-2-deoxy-4,6-O-ethylidene-.beta.-D-glucopyranosyl)-4'-demethyl
-4-epipodophyllotoxin. The mother liquor was chromatographed on
silica gel for separation and purification. The desired compound
was recovered in an amount of 15 mg.
EXAMPLE 2
Synthesis of
4-O-(3-amino-3-deoxy-4,6-O-ethylidene-.beta.-D-glucopyranosyl)-4'-demethyl
-4-epipodophyllotoxin
(1) Synthesis of
4-O-(2-O-acetyl-3-benzyloxycarbonylamino-2-deoxy-.beta.-D-glucopyranosyl)-
4'-benzyloxycarbonyl-4'-demethyl-4-epipodophyllotoxin
(a) 486 mg of 4'-benzyloxycarbonyl-4'-demethyl-4-epipodophyllotoxin
and 360 mg of 2,4,6-tri-O-acetyl-3-benzyloxycarbonylamino-
3-deoxy-.beta.-D-glucopyranose were dissolved in 1 ml of
dichloromethane. In the solution cooled at -20.degree. C., 0.5 ml
of Bf.sub.3.Et.sub.2 O was added dropwise over 3 minutes, and the
mixture was reacted for 30 minutes, with stirring, in an atmosphere
of argon. 0.5 ml of pyridine was added to terminate the reaction,
and then, the reaction mixture was diluted with 20 ml of
dichloromethane. The dilution was washed twice with 10 ml of water,
and the organic layer was dried over anhydrous Na.sub.2 SO.sub.4
and concentrated. The concentrate was separated and purified by
silica gel chromatography to obtain 500 mg of
4-O-(2,4,6-tri-O-acetyl-3-benzyloxycarbonylamino-3-deoxy-.beta.-D-glucopyr
anosyl)-4'-benzyloxycarbonyl-4'-demethyl-4-epipodophyllotoxin.
Specific rotation: [.alpha.].sub.D.sup.19 -40.1.degree.
(CHCl.sub.3)
(b) 500 mg of the compound obtained in the above step and 100 mg of
zinc acetate were dissolved, with heating, in a solvent mixture of
2 ml of methanol and 2 ml of dioxane. The solution was boiled for 6
hours under reflux, and the reaction mixture was concentrated to
dryness. 20 ml of dichloromethane and 10 ml of water were added to
the residue, and the mixture was shaken vigorously. The organic
layer was separated from the system, dried over anhydrous Na.sub.2
SO.sub.4, and concentrated. The concentrate was separated and
purified by silica gel chromatography to obtain 155 mg of
4-O-(2-O-acetyl-3-benzyloxycarbonylamino-3-deoxy-.beta.-D-glucopyranosyl)-
4'-benzyloxycarbonyl-4'-demethyl-4-epipodophyllotoxin.
Specific rotation: [.alpha.].sub.D.sup.18 -31.8.degree.
(CHCl.sub.3)
(2) Synthesis of
4-O-(3-amino-3-deoxy-4,6-O-ethylidene-.beta.-D-glucopyranosyl)-4'-demethyl
-4-epipodophyllotoxin
(2-1) (a) 140 mg of the compound obtained in Step (b) and 0.5 ml of
acetaldehyde diethylacetal were dissolved in 3 ml of acetonitrile.
5 mg of p-toluenesulfonic acid was added to the solution, and the
mixture was reacted for 2 hours at room temperature with stirring.
Sodium bicarbonate was added, and the insolubles were collected by
filtration. The filter cake was washed with dichloromethane, and
the washings were combined with the filtrate, followed by
concentrating the combined liquid. The concentrate was separated
and purified by chromatography to obtain 106 mg of
4-O-(2-acetyl-3-benzyloxycarbonylamino-3-deoxy-4,6-O-ethylidene-.beta.-D-g
lucopyranosyl)-4'-benzyloxycarbonyl-4-demethyl-4-epipodophyllotoxin.
Specific rotation: [.alpha.].sub.D.sup.25 -35.8.degree.
(CHCl.sub.3)
(b) 100 mg of the compound obtained in Step (a) was dissolved in 3
ml of ethyl acetate, and palladium black was added to the solution.
The mixture was stirred for 3 hours in a hydrogen gas stream for
reduction. The reaction mixture was filtered and concentrated. The
concentrate was separated and purified by silica gel chromatography
to obtain 39 mg of
4-O-(2-O-acetyl-3-amino-3-deoxy-4,6-O-ethylidene-.beta.-D-glucopyranosyl)-
4'-demethyl-4-epipodophyllotoxin.
NMR (CDCl.sub.3) .delta.1.35 (3H, d, CH.sub.3), ##STR8##
.delta.3.88 (6H, s, --OCH.sub.3), .delta.4.81 (1H, d, H-4),
.delta.5.97 (2H, s, --OCH.sub.2 O--), .delta.6.24 (2H, s, H-2',
6'), .delta.6.53 (1H, s, H-8), .delta.6.85 (1H, s, H-5)
(c) 29 mg of the compound obtained in Step (b) and 5 mg of zinc
acetate were dissolved in 3 ml of methanol, and the solution was
boiled for 45 minutes under reflux. The reaction mixture was poured
into 10 ml of water, and then extracted twice with 10 ml of
dichloromethane. The extract was concentrated, and the concentrate
was separated and purified by silica gel chromatography to obtain
7.4 mg of
4-O-(3-amino-3-deoxy-4,6-O-ethylidene-.beta.-D-glucopyranosyl)-4'-demethyl
-4-epipodophyllotoxin.
REFERENTIAL EXAMPLE
Synthesis of a Saccharide
700 mg of
3,4,6-tri-O-acetyl-2-benzyloxycarbonylamino-2-deoxy-.alpha.-D-glucopyranos
yl bromide [Bull, Chem. Soc. Japn., 34, 183 (1963)] was dissolved
in 2 ml of acetone, and with the solution cooled to 0.degree. C,
290 mg of silver carbonate and 20 ml of water were added. The
mixture was stirred for 1 hour at this temperature and filtered.
The filtrate was concentrated to obtain 580 mg of
3,4,6-tri-O-acetyl-2-benzyloxycarbonylamino-2-deoxy-.beta.-D-glucopyranose
In this Referential Example, if 2,4,6-tri-O-acetyl-
3-benzyloxycarbonylamino-3-deoxy-.alpha.D-glucopyranosyl bromide
was used as the starting compound and treated in the same way,
2,4,6-tri-0-acetyl-3-benzyloxycarbonylamino-3-deoxy-.beta.-D-glucopyranose
could be obtained.
* * * * *